It is commonplace in the electrical and electronics industries to encapsulate a circuit or network of connected electrical components such as resistors and capacitors in a matrix of insulating material. In some cases the encapsulated components are a simple subassembly of conductors such as lead wires and connector terminals. During application of fluid insulating material it is not safe to rely on the lead wires connecting the components to hold the several components of the circuit or subassembly in a predetermined spaced relation. One known way of maintaining spacing of the interconnected components is to preform a hollow plastic housing or carrier with internal compartments or supports for holding the components in the desired spaced relation. After locating the components in position inside the carrier, the carrier is then filled with fluid insulation such as a thermoplastic material by potting or injecting the plastic under pressure in a mold.
A major problem arises when filling the carrier, particularly with thermoplastic, because the hot plastic tends to shrink while cooling and setting after filling the carrier so that the filling draws away from the walls of the carrier opening up air space between the carrier and filling. The air space opened may be substantial, 0.01 to 0.02 inch for example, and may extend internally of the carrier so close to the electrical components as to greatly reduce the insulative integrity of the carrier and filling.
It is one object of the present invention to provide an insulation filled carrier of conductive components and a method of making such a conductor which eliminates the formation of air spaces and reduction of insulative integrity.